Positive sensitive resin composition and a process for forming a resist pattern therewith

ABSTRACT

A pattern can be precisely formed by irradiating, with an active energy beam, a positive sensitive resin composition according to this invention comprising a base polymer, an ether-bond-containing olefinic unsaturated compound and an acid-generating agent, where the base polymer is a copolymer comprising the structural units represented by formulas (1) to (3):  
                 
 
     where R 1  and R 3  are each independently hydrogen or methyl and R 2  is C 1 -C 6  straight or branched unsubstituted alkyl or C 1 -C 6  straight or branched substituted alkyl, wherein a, b and c are 0.05 to 0.7, 0.15 to 0.8 and 0.01 to 0.5, respectively and a+b+c=1.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a positive sensitive resin compositioncomprising a novel copolymer of 4-(1-methylethenyl)phenol, a(meth)acrylate and a (meth)acrylic acid (PIPE copolymer), anether-bond-containing olefinic unsaturated compound and anacid-generating agent, as well as a process for forming a resist patterntherewith. In particular, it relates to a positive sensitive resincomposition comprising a copolymer of 4-(1-methylethenyl)phenol, a(meth)acrylate and a (meth)acrylic acid useful as a base polymer, anether-bond-containing olefinic unsaturated compound and anacid-generating agent, as well as a process for forming a resist patternby applying or adhering the composition to a substrate and thenirradiating it with an active energy beam such as ultraviolet rays,visible light and heat rays for developing it.

[0003] 2.Description of the Related Art

[0004] A resist material in combination with an exposure technique hasbeen utilized in lithography such as patterned circuit formation in anelectron device and printing.

[0005] An application of such patterned circuit formation in an electrondevice may be, for example, a process for manufacturing a color filterfor a variety of multicolored liquid-crystal color displays such as aliquid-crystal color television.

[0006] Such a color filter has been conventionally manufactured by, forexample, screen printing and electrodeposition. However, as a colordisplay has been improved for its resolution, it has been more importantto refine a pattern. Thus, a variety of patterning processes utilizingphotolithography has been investigated.

[0007] For example, JP-A 8-94827 has disclosed a process formanufacturing a color filter comprising the steps of [1] forming atransparent conductive layer on a transparent substrate; [2] forming apositive photosensitive coating layer; [3] exposing a part of thetransparent conductive layer; [4] forming a colored area byelectrodeposition; and [5] repeating the steps [3] and [4] as required.Of these steps, a pattern refinement level depends on the steps [2] and[3], in which photolithography is used. In particular, it significantlydepends on a positive photosensitive composition applied on thetransparent conductive layer. The above invention employs a positivephotosensitive composition essentially comprising (a) a polymercontaining both carboxyl and hydroxyphenyl groups in one molecule, (b) acompound containing two or more vinyl ether groups in one molecule, and(c) a compound generating an acid by irradiating an active energy beam.

[0008] This photosensitive composition is developed as follows; byheating the film on which the positive photosensitive composition hasbeen applied, an addition reaction of the carboxyl group and/orhydroxyphenyl group with the vinyl ether group forms a crosslink, whichis insoluble to a solvent or an alkali developing solution, and then,after irradiating with an active energy beam and then, as necessary,heating the film, an acid generated in the irradiated area acts as acatalyst to cleave the crosslink structure and thus to again make theirradiated area soluble to a solvent or an alkali developing solution.For further improving a resolution, a preferable polymer (base polymer)in a positive photosensitive composition is one containing both carboxyland hydroxyphenyl groups in one molecule which meets all the followingfive requirements as much as possible;

[0009] (a) a higher solubility to a solution which solves a crosslinkingagent, an acid-generating gent and others (solvent solubility);

[0010] (b) a certain dissolution rate of the cloven crosslink moietiesin an alkali developing solution after exposure (dissolution rate in analkali developing solution);

[0011] (c) good diffusivity of an acid generated by irradiation with anactive energy beam (acid diffusivity);

[0012] (d) transparency of a photosensitive coating at an exposurewavelength (transparency); and

[0013] (e) thermal stability during the heating step after applicationof the film and exposure (thermal stability).

[0014] As an example of a polymer meeting these requirements somewhat, acopolymer from p-hydroxystyrene, n-butyl acrylate and acrylic acid hasbeen disclosed in, for example, JP-As 8-94827 and 8-94829. We have,however, investigated the copolymer for its performance and haveconcluded that it is insufficiently soluble in a solvent or thermallystable.

[0015] JP-A 61-293249 has disclosed a binary copolymer of4-(1-methylethenyl)phenol and n-butyl acrylate as an example of acopolymer for a resin composition exhibiting damping property. Thecopolymer has an extremely lower dissolution rate in an alkalideveloping solution and is poorly compatible with a vinyl ethercompound. It cannot be, therefore, used as it is.

SUMMARY OF THE INVENTION

[0016] An objective of this invention is to provide a positive sensitiveresin composition useful as the above photoresist material as well as aprocess for forming a resist pattern using the composition.

[0017] We have prepared a variety of copolymers as a resin component ina positive sensitive resin composition, using 4-(1-methylethenyl)phenoland different monomers, to investigate them for their relationshipbetween their basic physical properties and structures, and then havesurprisingly found that a copolymer of 4-(1-methyl-ethenyl)phenol, a(meth) acrylate and a (meth)acrylic acid as structural units in aparticular composition ratio can meet all the above five requirementsfor a photoresist material ((a) solvent solubility, (b) dissolution ratein an alkali developing solution, (c) acid diffusivity, (d) transparencyand (e) thermal stability).

[0018] This invention provides

[0019] (I) A positive sensitive resin composition comprising a basepolymer, an ether-bond-containing olefinic unsaturated compound and anacid-generating agent, where the base polymer is a copolymer comprisingthe structural units represented by formula (1):

[0020] where R¹ is hydrogen or methyl and R² is C₁-C₆ straight orbranched unsubstituted alkyl or C₁-C₆ straight or branched substitutedalkyl, and formula (3):

[0021] where R³ is hydrogen or methyl,

[0022] wherein a, b and c are 0.05 to 0.7, 0.15 to 0.8 and 0.01 to 0.5,respectively and a+b+c=1;

[0023] (II) A positive sensitive resin composition described in (I)where a compounding ratio of the copolymer comprising the structuralunits represented by formulas (1) to (3) and the ether-bond-containingolefinic unsaturated compound is 0.5 to 50/99.5 to 50 wt % as a ratio ofcopolymer/unsaturated compound based on their total wt % values, and theamount of the acid-generating agent is 0.1 to 40 wt parts to 100 wtparts of the total amount of the copolymer and the olefinic unsaturatedcompound;

[0024] (III) A positive sensitive resin composition described in (I)where R² in the structural unit represented by formula (2) is C₁-C₆straight or branched unsubstituted alkyl or C₁-C₆ straight or branchedhydroxylated alkyl;

[0025] (IV) A positive sensitive resin composition described in (I)where R² in the structural unit represented by formula (2) is selectedfrom the group consisting of methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl and 2-hydroxyethyl;

[0026] (V) A positive sensitive resin composition described in (I) wherea material giving the structural unit represented by formula (2) is a(meth)acrylate selected from the group consisting of methyl acrylate,ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,isobutyl acrylate, sec-butyl acrylate, 2-hydroxyethyl acrylate, methylmethacrylate, ethyl methacrylate, n-propyl methacrylate, isopropylmethacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butylmethacrylate and 2-hydroxyethyl methacrylate;

[0027] (VI) A positive sensitive resin composition described in (I)where for the copolymer, a in formula (1) is 0.20 to 0.45, b in formula(2) is 0.25 to 0.70, and c in formula (3) is 0.15 to 0.40, and a+b+c=1;

[0028] (VII) A positive sensitive resin composition described in (I) or(V) where the copolymer comprising the structural units representedformulas (1), (2) and (3) is an alternating copolymer comprising thestructural units represented by formula (4):

[0029] where R¹ is hydrogen or methyl and R² is C₁-C₆ straight orbranched unsubstituted alkyl or C₁-C₆ straight or branched substitutedalkyl, and formula (5):

[0030] where R³ is hydrogen or methyl, in which the total content ofthese structural units is at least 60 mol %;

[0031] (VIII) A positive sensitive resin composition described in any of(I) to (VII) comprising a photosensitizer;

[0032] (IX) A positive sensitive resin composition described in (VIII)where a compounding ratio of the copolymer comprising the structuralunits represented by formulas (1) to (3) and the ether-bond-containingolefinic unsaturated compound is 0.5 to 50/99.5 to 50 wt % as a ratio ofcopolymer/unsaturated compound based on their total wt % values; theamount of the acid-generating agent is 0.1 to 40 wt parts to 100 wtparts of the total amount of the copolymer and the olefinic unsaturatedcompound; and the amount of the photosensitizer is 0.1 to 20 wt parts to100 wt parts of the total amount of the copolymer, the olefinicunsaturated compound and the acid-generating agent;

[0033] (X) A positive ultraviolet sensitive resist comprising acomposition described in any of (I) to (VII), whose part irradiated withultraviolet rays is soluble or dispersible in an organic solvent or anaqueous developing solution, and whose unirradiated part issubstantially insoluble and undispersible in an organic solvent or anaqueous developing solution;

[0034] (XI) A positive thermally sensitive resist comprising acomposition described in any of (I) to (VII), whose part irradiated withheat rays is soluble or dispersible in an organic solvent or an aqueousdeveloping solution, and whose unirradiated part is substantiallyinsoluble and undispersible in an organic solvent or an aqueousdeveloping solution;

[0035] (XII) A positive visible-light sensitive resist comprising acomposition described in (VIII) to (IX), whose part irradiated withvisible light is soluble or dispersible in an organic solvent or anaqueous developing solution, and whose unirradiated part issubstantially insoluble and undispersible in an organic solvent or anaqueous developing solution;

[0036] (XIII) An organic-solvent type resin composition which isprepared by dissolving or dispersing the positive sensitive resincomposition described in (I) to (IX) in an organic solvent.

[0037] (XIV) An aqueous resin composition which is prepared bydissolving or dispersing the positive sensitive resin compositiondescribed in (I) to (IX) in water.

[0038] (XV) An aqueous resin composition described in (XIV) wherein thedissolving or dispersing is carried out by neutralizing an anionic groupin the positive sensitive resin composition with an alkali.

[0039] (XVI) A positive dry film comprises a substrate and a resistfilm, where the resist film is formed by applying a positive sensitiveresin composition described in (I) to (IX) to a surface of thesubstrate.

[0040] (XVII) A process for forming a resist pattern consistingessentially of the steps of:

[0041] (1) applying a positive sensitive resin composition described inany of (I) to (IX) to a substrate surface to form a resist film;

[0042] (2) irradiating the resist film on the substrate with an activeenergy beam directly or via a mask film to form a desired pattern(image) on the film; and

[0043] (3) developing the resist film to form a resist pattern on thesubstrate;

[0044] (XVIII) A process for forming a resist pattern consistingessentially of the steps of:

[0045] (1) applying a positive sensitive resin composition described inany of (I) to (IX) to a supporting substrate surface to form a positivedry film comprising a solid positive sensitive resin film;

[0046] (2) adhering the dry film on an adhered substrate surface in amanner that the adhered substrate surface faces the resin film of thedry film;

[0047] (3) irradiating the dry film surface with an active energy beamdirectly or via a mask film with or without peeling off the supportingsubstrate of the dry film, to form a desired pattern; and

[0048] (4) developing the resist film, after peeling off the supportingsubstrate when it has not been removed in the step (3), to form a resistpattern on the substrate.

[0049] This invention involves a positive sensitive resin compositioncomprising a copolymer of 4-(1-methyl-ethenyl)phenol, a (meth)acrylateand a (meth)acrylic acid, an ether-bond-containing olefinic unsaturatedcompound, and an acid-generating agent. A resist film formed from thecomposition may be, therefore, heated to be a crosslinked filmconsiderably resistant to a developing solution, whose part irradiatedwith an active energy beam may be in turn cleaved crosslink to becomesoluble in a developing solution. The resist film may be, therefore,highly effective for forming a fine and sharp resist pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050]FIG. 1 shows an ¹H-NMR spectrum of the copolymer of4-(1-methylethenyl)phenol, methyl acrylate and acrylic acid prepared inExample 1, in d₆-dimethylsulfoxide.

[0051]FIG. 2 shows a ¹³C-NMR spectrum of the copolymer of4-(1-methylethenyl)phenol, methyl acrylate and acrylic acid prepared inExample 1, in d₆-dimethylsulfoxide.

[0052]FIG. 3 shows a GPC elution curve for the copolymer of4-(1-methylethenyl)phenol, methyl acrylate and acrylic acid prepared inExample 1.

[0053]FIG. 4 shows spectrophotometry for ultraviolet and visible regionfor the copolymer of 4-(1-methylethenyl)phenol, methyl acrylate andacrylic acid prepared in Example 1.

[0054]FIG. 5 shows thermogravimetry for the copolymer of4-(1-methylethenyl)phenol, methyl acrylate and acrylic acid prepared inExample 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] A base resin used in a composition of this invention is acopolymer comprising the structural units represented by formulas (1),(2) and (3) (hereinafter, sometimes referred to simply as “thecopolymer”). The rates, a, b and c, are 0.05 to 0.7, 0.15 to 0.8, and0.01 to 0.5, respectively, and a+b+c=1.

[0056] In formula (2), R² is C₁-C₆ straight or branched unsubstitutedalkyl or C₁-C₆ straight or branched substituted alkyl, including, forexample, unsubstituted alkyls such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, cyclohexyl andcyclopentyl; hydroxylated alkyls such as hydroxymethyl, 1-hydroxyethyl,2-hydroxyethyl, 1-hydroxy-n-propyl, 2-hydroxy-n-propyl,3-hydroxy-n-propyl, 1-hydroxyisopropyl, 2,3-dihydroxy-n-propyl,1-hydroxy-n-butyl, 2-hydroxy-n-butyl, 3-hydroxy-n-butyl and4-hydroxy-n-butyl; alkoxylated alkyls such as methoxymethyl,ethoxymethyl, 1-methoxyethyl, 2-methoxyethyl, 2-ethoxyethyl,1-methoxy-n-propyl, 2-methoxy-n-propyl, 4-methoxy-n-butyl,2-(2-ethoxyethoxy)ethyl, glycidyl, tetrahydrofurfuryl and2-tetrahydrofuryl; halogenated alkyls such as 2,2,2-trifluoroethyl,hexafluoroisopropyl, 2,2,3,4,4,4-hexafluorobutyl, 2-chloroethyl,trichloroethyl, 2-bromoethyl and heptafluoro-2-propyl; cyanated alkylssuch as 2-cyanoethyl; dialkylaminated alkyls such as2-(dimethylamino)ethyl, 3-(dimethylamino)propyl and3-dimethylamino-neopentyl.

[0057] Preferably, R² is C₁-C₆ straight or branched unsubstituted orhydroxylated alkyl; more preferably, methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl or 2-hydroxyethyl. The copolymer used inthe composition of the present invention may comprise two or more typesof the structural unit represented by formula (2). Specifically, acopolymer comprising four or more structural units; for example, acopolymer comprising structural units of one type of formula (1), two ormore types of formula (2) and one type of formula (3), may be used forthe composition of this invention.

[0058] In formula (3), R³ is hydrogen or methyl. Again, either or bothof these structural units represented by formula (3) may be contained ina copolymer In the copolymer used in the composition of this invention,the composition ratios of the structural units represented by formulas(1), (2) and (3) are considerably important. Assuming that there is arelationship a+b+c=1 between the composition ratios of a, b and c, a, band c are, in an embodiment, 0.05 to 0.7, 0.15 to 0.8 and 0.01 to 0.5,respectively; in a preferable embodiment, 0.1 to 0.5, 0.20 to 0.75 and0.1 to 0.4, respectively; in a more preferable embodiment, 0.20 to 0.45,0.25 to 0.70 and 0.15 to 0.40, respectively. When two or more types ofthe structural units represented by formulas (2) and/or (3) are present,the composition ratio of b or c is its total composition ratio.Composition ratios a, b and c are determined by ¹H-NMR and ¹³C-NMR.

[0059] The copolymer used in the composition of this invention may be acopolymer in which the structural units represented by formulas (1), (2)and (3) are randomly copolymerized; these three structural units arealternately copolymerized; or these units are block-copolymerized. Apreferable copolymer is one largely comprising a moiety in which thestructural unit represented by formula (1) and the structural unitsrepresented by formulas (2) and (3) are alternately copolymerized.Specifically, the most preferable copolymer is an alternating copolymercomprising structural units represented by formula (4):

[0060] where R¹ is hydrogen or methyl and R² is C₁-C₆ straight orbranched unsubstituted alkyl or C₁-C₆ straight or branched substitutedalkyl, and formula (5):

[0061] where R³ is hydrogen or methyl,

[0062] wherein the total content of these structural units is at least50 mol%, preferably at least 60 mol%.

[0063] A weight-average molecular weight (Mw) of the copolymer used inthe composition of this invention may vary, depending on itsapplication. For example, when used as a base polymer in aphotosensitive composition, it is generally 3,000 to 100,000, preferably4,000 to 70,000, more preferably 5,000 to 50,000.

[0064] Molecular-weight dispersion (Mw/Mn) is generally 1.0 to 3.5,preferably 1.0 to 3.0, and more preferably 1.0 to 2.5. A weight-averagemolecular weight and molecular-weight dispersion are determined by gelpermeation chromatography (GPC) which is converted into polystyrene.

[0065] A glass transition point for the copolymer used in thecomposition of this invention may depend on its composition orcomposition ratio, but generally 0 to 200° C., preferably 10 to 150° C.,more preferably 30 to 120° C. A glass transition point is determinedwith a differential scanning calorimeter (DSC).

[0066] The copolymer used in the composition of this invention exhibitsexcellent transparency. Its transmittance at 350 nm is generally atleast 70%/μm, preferably at least 90%/μm, more preferably at least95%/μm. A transmittance is determined at 30 nm for a 1 μm thick filmformed on a quartz substrate by spin coating, with a spectrophotometerfor ultraviolet and visible region.

[0067] Furthermore, the copolymer used in the composition of thisinvention exhibits excellent solubility in an aqueous alkali solution. Adissolution rate in a 2.38 wt % aqueous solution of tetramethylammoniumhydroxide is generally 1 μm/min, and preferably 5 μm/min. A dissolutionrate is determined by applying the copolymer on a copper-coatedsubstrate with a bar coater, heating it at 80° C. for 30 minutes to forma film 5 μm of thickness, soaking it in a 2.38 wt % aqueous solution oftetramethylammonium hydroxide and then measuring the film thickness witha dial thickness gage.

[0068] The copolymer used in the composition of this invention may beprepared by heating a mixture of (a) 4-(1-methylethenyl)phenol, (b) a(meth)acrylate represented by formula (6):

[0069] where R¹ is hydrogen or methyl and R² is C₁-C₆ straight orbranched unsubstituted alkyl or C₁-C₆ straight or branched substitutedalkyl, (c) a (meth)acrylic acid represented by formula (7):

[0070] where R³ is hydrogen or methyl, (d) a radical-polymerizationinitiator and (e) a solvent in a particular molar ratio.

[0071] One material, 4-(1-methylethenyl)phenol, may be readily preparedby thermal decomposition of bisphenol A (e.g., JP-B 56-52886).

[0072] Examples of the (meth)acrylate represented by formula (6) asanother material are C₁-C₆ straight or branched unsubstituted acrylatesor methacrylates and C₁-C₆ straight or branched substituted acrylates ormethacrylates, including unsubstituted alkyl acrylates such as methylacrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate,cyclohexyl acrylate and cyclopentyl acrylate; hydroxylated-alkylacrylates such as hydroxymethyl acrylate, 1-hydroxyethyl acrylate,2-hydroxyethyl acrylate, 1-hydroxy-n-propyl acrylate, 2-hydroxy-n-propylacrylate, 3-hydroxy-n-propyl acrylate, 1-hydroxyisopropyl acrylate,2,3-dihydroxypropyl acrylate, 1-hydroxy-n-butyl acrylate,2-hydroxy-n-butyl acrylate, 3-hydroxy-n-butyl acrylate and4-hydroxy-n-butyl acrylate; alkoxylated-alkyl acrylates such asmethoxymethyl acrylate, ethoxymethyl acrylate, 1-methoxyethyl acrylate,2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 1-methoxy-n-propylacrylate, 2-methoxy-n-propyl acrylate, 4-methoxy-n-butyl acrylate,2-(2-ethoxyethoxy)ethyl acrylate, glycidyl acrylate, tetrahydrofurfurylacrylate and 2-tetrahydrofuryl acrylate; halogenated-alkyl acrylatessuch as 2,2,2-trifluoroethyl acrylate, hexafluoroisopropyl acrylate,2,2,3,4,4,4-hexafluorobutyl acrylate, 2-chloroethyl acrylate,trichloroethyl acrylate, 2-bromoethyl acrylate and heptafluoro-2-propylacrylate; cyanated-alkyl acrylates such as 2-cyanoethyl acrylate;dialkylaminated-alkyl acrylates such as 2-(dimethylamino)ethyl acrylate,3-(dimethylamino)propyl acrylate and 3-dimethylamino-neopentyl acrylate;unsubstituted alkyl methacrylates such as methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butylmethacrylate, cyclohexyl methacrylate and cyclopentyl methacrylate;hydroxylated-alkyl methacrylates such as hydroxymethyl methacrylate,1-hydroxyethyl methacrylate, 2-hydroxyethyl methacrylate,1-hydroxy-n-propyl methacrylate, 2-hydroxy-n-propyl methacrylate,3-hydroxy-n-propyl methacrylate, 1-hydroxyisopropyl methacrylate,2,3-dihydroxypropyl methacrylate, 1-hydroxy-n-butyl methacrylate,2-hydroxy-n-butyl methacrylate, 3-hydroxy-n-butyl methacrylate and4-hydroxy-n-butyl methacrylate; alkoxylated-alkyl methacrylates such asmethoxymethyl methacrylate, ethoxymethyl methacrylate, 1-methoxyethylmethacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate,1-methoxy-n-propyl methacrylate, 2-methoxy-n-propyl methacrylate,4-methoxy-n-butyl methacrylate, 2-(2-ethoxyethoxy)ethyl methacrylate,glycidyl methacrylate, tetrahydrofurfuryl methacrylate and2-tetrahydrofuryl methacrylate; halogenated-alkyl methacrylates such as2,2,2-trifluoroethyl methacrylate, hexafluoroisopropyl methacrylate,2,2,3,4,4,4-hexafluorobutylmethacrylate, 2-chloroethyl methacrylate,trichloroethyl methacrylate, 2-bromoethyl methacrylate andheptafluoro-2-propyl methacrylate; cyanated-alkyl methacrylates such as2-cyanoethyl methacrylate; dialkylaminated-alkyl methacrylates such as2-(dimethylamino)ethyl methacrylate, 3-(dimethylamino)propylmethacrylate and 3-dimethylamino-neopentyl methacrylate.

[0073] Among others, preferable (meth)acrylates are unsubstituted alkylacrylates, hydroxylated-alkyl acrylates, unsubstituted alkylmethacrylates and hydroxylated-alkyl methacrylates; more preferable(meth)acrylates are methyl acrylate, ethyl acrylate, n-propyl acrylate,isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butylacrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, sec-butyl methacrylate and2-hydroxyethyl methacrylate. These acrylates may be used alone,concurrently or as a mixture of two or more. In the latter case, theremay be formed a copolymer where two or more types of the structural unitrepresented by formula (2) are randomly copolymerized, in which acomposition ratio b is the total of the composition ratios for two ormore types of the structural unit represented by formula (2).

[0074] A (meth)acrylic acid represented by formula (7) as anothermaterial is acrylic or methacrylic acid, which may be used alone,concurrently or as a mixture of two.

[0075] These 4-(1-methylethenyl)phenol, a (meth)acrylate or a (meth)acrylic acid may contain additives; for example, a stabilizer such as analkali compound including potassium hydroxide or a polymerizationinhibitor. These materials are preferably subject to a commonpurification process such as recrystallization and distillation forremoving a stabilizer before their use, while commercially availablematerials may be used as they are without any purification process.

[0076] The amounts of 4-(1-methylethenyl)phenol, a (meth)acrylate and a(meth)acrylic acid are preferably selected to be their compositionratios in a desired copolymer. Specifically, the mole fractions of4-(1-methylethenyl)phenol, a (meth)acrylate and a (meth)acrylic acid are0.05 to 0.7, 0.15 to 0.8, and 0.01 to 0.5, respectively and the total ofthese mole fractions is 1; preferably 0.1 to 0.5, 0.20 to 0.75, and 0.1to 0.4, respectively; more preferably 0.20 to 0.45, 0.25 to 0.70, and0.15 to 0.40, respectively.

[0077] A radical-polymerization initiator in the preparation process ofthe copolymer may be any of initiators used in a common radicalpolymerization; for example, azo initiators such asazobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile,azobiscyclohexanecarbonitrile, azobis-2-amidinopropane hydrochloride,dimethyl azobisisobutyrate, azobisisobutylamidine hydrochloride and4,4′-azobis-4-cyanovaleric acid; peroxide initiators such as benzoylperoxide, 2,4-dichlorobenzoyl peroxide, di-tert-butyl peroxide, lauroylperoxide, acetyl peroxide, peroxydiisopropyl dicarbonate, cumenehydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, p-menthanehydroperoxide, pinane hydroperoxide, methyl ethyl ketone peroxide,cyclohexanone peroxide, diisopropyl peroxydicarbonate, tert-butylperoxylaurate, di-tert-butyl peroxyphthalate, dibenzyl oxide and2,5-dimethylhexane-2,5-dihydroperoxide; and redox initiators such asbenzoyl peroxide-N,N-dimethylaniline and peroxodisulfuric acid-sodiumhydrogen sulfite.

[0078] Among others, preferable initiators are azo initiators andperoxide initiators. More preferable initiators areazobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile,azobiscyclohexanecarbonitrile, dimethyl azobisisobutyrate, benzoylperoxide, 2,4-dichlorobenzoyl peroxide, di-tert-butyl peroxide, lauroylperoxide, peroxydiisopropyl dicarbonate and acetyl peroxide. Theseradical-polymerization initiators may be used alone or two or more ofthem may be used concurrently or sequentially.

[0079] These initiators may be used in a mole fraction of 0.0001 to 0.1,preferably 0.001 to 0.1, more preferably 0.005 to 0.05, to the totalamount of (a) 4-(1-methylethenyl)phenol, (b) a (meth)acrylaterepresented by formula (6) and (c) a (meth)acrylic acid represented byformula (7). In this invention, all of these radical-polymerizationinitiators may be charged at the beginning of heating, or all or a partof these may be added after initiation of heating as long as the totalamount of the initiators is within the limits.

[0080] Any solvent may be used as long as it does not adversely affectthe desired reaction; for example, ketones such as acetone, methyl ethylketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone andγ-butyrolactone; alcohols such as n-propyl alcohol, isopropyl alcohol,n-butyl alcohol, tert-butyl alcohol, n-octanol, 2-ethylhexanol andn-dodecyl alcohol; glycols such as ethylene glycol, propylene glycol anddiethylene glycol; ethers such as ethylene glycol dimethyl ether,ethylene glycol diethyl ether, diethylene glycol dimethyl ether,diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether,tetrahydrofuran and dioxane; alcohol ethers such as ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, propylene glycolmonomethyl ether, propylene glycol monoethyl ether and diethylene glycolmonomethyl ether; esters such as n-propyl formate, isopropyl formate,n-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate,isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate,n-hexyl acetate, methyl propionate, ethyl propionate and methylbutyrate; monooxycarboxylates such as methyl 2-oxypropionate, ethyl2-oxypropionate, n-propyl 2-oxypropionate, isopropyl 2-oxypropionate,ethyl 2-oxy-2-methylpropionate and methyl 2-oxy-3-methylbutyrate;alkoxycarboxylates such as ethyl methoxyacetate, ethyl ethoxyacetate,methyl 3-methoxypropionate, ethyl 3-methoxypropionate and methyl3-ethoxypropionate; cellosolve esters such as cellosolve acetate, methylcellosolve acetate, ethyl cellosolve acetate and butyl cellosolveacetate; aromatic hydrocarbons such as benzene, toluene and xylenes;halogenated hydrocarbons such as trichloroethylene, chlorobenzene anddichlorobenzene; and amides such as dimethylacetamide,dimethylformamide, N-methylacetamide, N-methylpyrrolidone andN,N′-dimethylimidazolidinone.

[0081] These solvents may be used alone or as a mixture of two or more.It is preferable that these solvents are used to give a homogeneousreaction solution, but the reaction mixture may consist of heterogeneoustwo or more phases. The amount of the solvent may vary depending on avariety of factors such as materials to be used, the type and the amountof a radical-polymerization initiator, and the molecular weight of adesired copolymer, but generally 5 to 10,000 wt parts, preferably 20 to5,000 wt parts, more preferably 50 to 1,000 wt parts, to 100 wt parts ofthe total amount of the materials.

[0082] The polymerization reaction may be conducted in any style ofbatch, semi-batch or continuous flow, as long as (a)4-(1-methylethenyl)phenol, (b) a (meth)acrylate represented by formula(6), (c) a (meth)acrylic acid represented by formula (7), (d) aradical-polymerization initiator; (e) a solvent and others areeffectively mixed and contacted with each other. Generally, all of thesematerials may be charged in a reactor before heating, or alternativelymaterials, a radical-polymerization catalyst and a solvent may becontinuously or intermittently added into a reactor in which at least apart of the solvent has been charged.

[0083] Among these styles, the reaction is preferably conducted,maintaining the total concentration of 4-(1-methylethenyl)phenol, a(meth)acrylate and a (meth)acrylic acid at 20 wt % or less in thereaction system throughout the heating step. In particular, as4-(1-methylethenyl)phenol, a (meth)acrylate and a (meth)acrylic acid areconsumed by polymerization, these materials are continuously orintermittently supplied into the reaction system in an appropriateamount. More specifically, the materials and a radical-polymerizationinitiator may be continuously or intermittently added into a reactor inwhich a solvent has been charged; the materials may be continuously orintermittently added into a reactor in which a solvent and aradical-polymerization initiator have been charged; into a reactor inwhich parts of a solvent and a radical-polymerization initiator havebeen charged, the materials and the remaining solvent andradical-polymerization initiator may be continuously or intermittentlyadded; or alternatively, into a reactor in which parts of the materials,a solvent and a radical-polymerization initiator have been charged, theremaining materials, solvent and radical-polymerization initiator may becontinuously or intermittently added.

[0084] In this preparation process, a polymerization reaction proceedsby heating. Heating may be conducted at any temperature which may allowthe reaction to proceed. The temperature may vary depending on variousfactors such as a polymerization degree, a composition and a compositionratio in a desired polymer and the types and the amounts of aradical-polymerization initiator and a solvent, but generally 50 to 250°C., preferably 50 to 180° C., more preferably 60 to 160° C.

[0085] A polymerization duration may also vary depending on variousfactors such as a polymerization degree, a composition and a compositionratio in a desired polymer and the types and the amounts of aradical-polymerization initiator and a solvent, but generally up to 40hours, preferably 0.01 to 20 hours. The reaction may be conducted undera reduced, ambient or elevated pressure.

[0086] The polymerization reaction is preferably conducted in anatmosphere of an inert gas such as nitrogen and argon, but may beconducted in the presence of molecular oxygen, e.g., in the air.

[0087] In the preparation process, additives such as a phenol compoundmay be used for, e.g., improving a yield of -the copolymer and alteringthe sequence of the structural units in the copolymer.

[0088] After the completion of the polymerization reaction, a productcopolymer may be isolated from the reaction mixture by a commontechnique such as solvent extraction, fractional precipitation and filmevaporation. The mixture may be sometimes used as it is in a subsequentapplication without isolating a desired product copolymer.

[0089] In the composition of this invention, anether-bond-containing-olefinic unsaturated compound may be a low or highmolecular weight compound comprising about 1 to 4, preferably 2 to 4unsaturated ether groups such as vinyl ether represented by formula—R′—O—CH═CH₂ where R′ is C₁-C₆ straight or branched alkylene such asmethylene, ethylene, propylene and butylene, 1-propenyl ether and1-butenyl ether, in one molecule.

[0090] Examples of such an ether-bond-containing-olefinic unsaturatedcompound are condensation products of a polyphenol such as bisphenol A,bisphenol F, bisphenol S and a phenol resin or a polyol such as ethyleneglycol, propylene glycol, trimethylolpropane, trimethylolethane andpentaerythritol, with a halogenated-alkyl vinyl ether such aschloroethyl vinyl ether. In particular, a condensation product of theabove polyphenol with a halogenated-alkyl vinyl ether is preferable inthe light of its etching resistance and precision of a pattern to beformed.

[0091] The ether-bond-containing olefinic unsaturated compound may be anether-bond-containing olefinic polyurethane comprising about 1 to 4,preferably 2 to 4 unsaturated ether groups described above and at leastone urethane bond in one molecule.

[0092] Examples of such a polyurethane unsaturated compound are areaction product of a polyisocyanate described below, a hydroxyalkylvinyl ether and, as necessary, the above compound having at least twohydroxy groups in one molecule; and a condensation product of apolyphenol such as bisphenol A, bisphenol F, bisphenol S and a phenolresin or a polyol such as ethylene glycol, propylene glycol,trimethylolpropane, trimethylolethane and pentaerythritol, apolyisocyanate described below, and a halogenated-alkyl vinyl ether suchas chloroethyl vinyl ether. In particular, a reaction product of apolyisocyanate and a hydroxyalkyl vinyl ether is preferable in the lightof its etching resistance and precision of a pattern to be formed.

[0093] Examples of the above polyisocyanate include aliphaticdiisocyanates such as hexamethylene diisocyanate, trimethylenediisocyanate, 1,4-tetramethylene diisocyanate, pentamethylenediisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate,trimethylhexamethylene diisocyanate, dimer acid diisocyanate, lysinediisocyanate, 2,3-butylene diisocyanate and 1,3-butylene diisocyanate;alicyclic diisocyanates such as isophorone diisocyanate, 4,4′-methylenebis(cyclohexylisocyanate), methylcyclohexane-2,4-( or-2,6-)diisocyanate, 1,3-(or 1,4-)di(isocyanatomethyl)cyclohexane,1,4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate and1,2-cyclohexane diisocyanate; aromatic diisocyanates such as p-xylylenediisocyanate, meta-xylylene diisocyanate, tetramethylxylylenediisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate,1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate,4,4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate, (m- orp-)phenylene diisocyanate, 4,4′-biphenylene diisocyanate,3,3′-dimethyl-4,4′-biphenylene diisocyanate,bis(4-isocyanatophenyl)sulfone and isopropylidenebis(4-phenylisocyanate). Other polyisocyanates may be used; for example,polyisocyanates comprising at least three isocyanate groups such astriphenylmethane-4,4′,4″-triisocyanate, 1,3,5-triisocyanatobenzene,2,4,6-triisocyanatotoluene,4,4′-dimethyldiphenylmethane-2,2′,5,5′-tetraisocyanate; an adductobtained by reacting a polyol such as ethylene glycol, propylene glycol,1,4-butylene glycol, polyalkylene glycol, trimethylolpropane and hexanetriol with a polyisocyanate in an amount giving excessive isocyanategroups to the hydroxy groups in the polyol; biuret type adducts such ashexamethylene diisocyanate, isophorone diisocyanate, tolylenediisocyanate, xylylene diisocyanate, 4,4′-diphenylmethane diisocyanateand 4,4′-methylene bis(cyclohexylisocyanate); and isocyanurate-ring typeadducts.

[0094] Among others, preferable polyisocyanates are isophoronediisocyanate, xylylene diisocyanate, tolylene diisocyanate,1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylenediisocyanate and 2,4,4-trimethylhexamethylene diisocyanate.

[0095] Preferably, the ether-bond-containing olefinic unsaturatedcompound is liquid at an ambient temperature or has a melting orsoftening point of below 150° C., particularly below 130° C. because anaddition reaction between the carboxyl groups in the copolymer and theether groups in the unsaturated compound may be accelerated duringheating before irradiating with an active energy beam.

[0096] A compounding ratio of the copolymer and theether-bond-containing olefinic unsaturated compound is 0.5 to 50/99.5 to50 wt %, preferably 1 to 30/99 to 70 wt %, more preferably 1 to 15/99 to85 wt % as a ratio of copolymer/ether-bond-containing olefinicunsaturated compound based on their total wt % values. If the copolymeris contained at less than 0.5 wt %, i.e., the ether-bond-containingolefinic unsaturated compound is contained at more than 99.5 wt %,resistance to a developing solution of an unirradiated part tends to bereduced. On the other hand, if the copolymer is contained at more than50 wt %, i.e., the ether-bond-containing olefinic unsaturated compoundis contained at less than 50 wt %, sensitivity and storage stability maytend to be reduced.

[0097] The acid-generating agent used in the composition of thisinvention is a compound or mixture generating an acid when irradiatedwith an active energy beam, which, in turn, acts as a catalyst fordecomposing a resist film crosslinked by the reaction of the copolymerwith the olefinic unsaturated compound. Any known acid-generating agentmay be any used.

[0098] Examples of a compound or mixture used as an acid-generatingagent are onium salts such as ammonium, phosphonium, sulfonium, seleniumand iodonium salts; diazonium salts; halogenated compounds; acombination of an organometallic/organohalogen compounds; benzoin oro-nitrobenzyl ester of a strong acid such as toluenesulfonic acid; andN-hydroxyamides and N-hydroxyimidosulfonates described in U.S. Pat. No.4,371,605. Arylnaphthoquinone diazide-4-sulfonates may be used.

[0099] Another effective group of acid-generating agents includesoligomers or polymers to which is added an anion group comprising anaromatic onium-acid-generating agent as a positive counter ion. Suchpolymers have been described in, for example, Column 9, lines 1 to 68and Column 10, lines 1 to 14 in U.S. Pat. No.4,661,429, which is hereinincorporated by reference.

[0100] Another suitable acid-generating agent is ATASS, i.e,3-(9-anthracenyl)propyldiphenylsulfonium hexafluoroantimonate, in whichanthracene and sulfonium salt is linked via a chain consisting of threecarbons. Other acid-generating agents which may be used includediphenyliodonium tosylate, benzoin tosylate and triarylphosphoniumhexafluoroantimonate.

[0101] Besides the above acid-generating agents, for example, iron-arenecomplexes, ruthenium-arene complexes, silanol-metal chelate complexes,triazines, diazidonaphthoquinones, sulfonates and sulfonimide esters.Photo acid-generating agents described in JP-As 7-146552, 11-237731(naphthalimidylsulfonate) and 10-204407 (ruthenocene compounds) may bealso used.

[0102] Photo acid-generating agents suitable to exposure by lightirradiation are diaryliodonium and triarylsulfonium salts. These aregenerally present in a form of complex metal-halide such astetrafluoroborate, hexafluoroantimonate, hexafluoroarsenate andhexafluorophosphate.

[0103] When the composition is used in irradiating with heat rays suchas infrared ray, a thermal acid-generating agent such as those describedin JP-As 1-96169, 2-1470, 2-255646, 2-268173, 3-11044, 3-115262, 4-1177,4-327574, 4-308563, 4-328106, 5-132461, 5-132462, 5-140132, 5-140209,5-140210, 5-170737, 5-230190, 5-230189, 6-271532, 6-271544, 6-321897,6-321915, 6-345726, 6-345733, 7-25852, 7-25863 and 7-89909,JP-A1-95/501581, and International Patent Publication WO 97/08141 may beused in addition to the above acid-generating agent.

[0104] A compounding ratio of the acid-generating agent is preferablyabout 0.1 to 40 wt parts, particularly about 0.2 to 20 wt parts to 100wt parts of the total amount of the copolymer and the olefinicunsaturated compound.

[0105] When the composition of this invention is used in irradiationwith visible light (400 nm to 520 nm), it is preferable to add aphotosensitizer. A photosensitizer is a compound which may be excited byabsorbing visible light to interact with a copolymer or anacid-generating agent. The interaction may include energy or electrontransfer from the excited photosensitizer to the copolymer oracid-generating agent. Any known photosensitizer may be used as long asit has the above properties.

[0106] A variety of known photosensitive dyes may be used as aphotosensitizer; for example, thioxanthene, xanthene, ketone,thiopyrylium salt, base styryl, merocyanine, 3-substituted coumarin,3,4-substituted coumarin, cyanine, acridine, thiazine, phenothiazine,anthracene, coronene, benzanthracene, perylene, merocyanine,ketocoumarin, fumarin and borate dyes. These may be used alone or incombination of two or more. Borate photosensitive dyes which may be usedinclude those described in JP-As 5-241338, 7-5685, 7-225474, 8-6245,7-219223, 11-116612, 11-100408 and 10-273504.

[0107] A compounding ratio of the photosensitizer is up to 20 wt parts,preferably about 0.1 to 10 wt parts, particularly about 0.1 to 5 wtparts to 100 wt parts of the total amount of the copolymer, the olefinicunsaturated compound and the acid-generating agent.

[0108] When a film formed from the composition of this invention isheated, a carboxyl group and an unsaturated ether group in the copolymerform a crosslink via addition reaction, to make the film insoluble to asolvent or aqueous alkali solution. Subsequently, by irradiating it withan active energy beam and then heating it, an acid is generated, whichacts as a catalyst to cleave the crosslink structure. Thus, the exposedpart again becomes soluble to a solvent or aqueous alkali solution.

[0109] Thus, in the composition, the acid generated by irradiating theformed film with an active energy beam allows acid hydrolysis to proceedin the exposed part. To facilitate the acid hydrolysis, it is preferablethat moisture is present. The composition of this invention may,therefore, contain a hydrophilic resin such as polyethylene glycol,polypropylene glycol, methyl cellulose and ethyl cellulose forfacilitating uptake of moisture adequate for the above reaction by anapplied film. The amount of such a hydrophilic resin is generally up to20 wt parts, preferably 0.1 to 10 wt parts to 100 wt parts of the resincomposition.

[0110] The composition of this invention may, as necessary, containanother resin insoluble or soluble (or dispersible) in water or anorganic solvent for improving or reducing its solubility in an organicsolvent or aqueous developing solution; for example, a phenol resin, apolyester resin, a (meth)acrylic resin, a vinyl resin, a vinyl acetateresin, an epoxy resin, a silicone resin, a fluororesin, combination oftwo or more, and their modified products.

[0111] The composition of this invention may contain a plasticizer(e.g., a phthalate), a polyester resin and/or a (meth)acrylic resin forendowing a film formed from the composition of this invention withappropriate flexibility and/or non-adherence.

[0112] The composition of this invention may, as necessary, contain afluidity modifier, a plasticizer and/or a coloring agent such as a dyeand a pigment.

[0113] The composition of this invention may be used as anorganic-solvent type resin composition such as an organic-solvent typeUV sensitive resin composition, an organic-solvent type visible-lightsensitive resin composition and an organic-solvent type thermallysensitive resin composition or an aqueous resin composition such as anaqueous UV sensitive resin composition, an aqueous visible-lightsensitive resin composition and an aqueous thermally sensitive resincomposition.

[0114] The above organic-solvent type resin composition may be preparedby dissolving or dispersing the positive sensitive resin composition inan organic solvent such as ketones, esters, ethers, cellosolves,aromatic hydrocarbons, alcohols and halogenated hydrocarbons. Thecomposition may be applied to a substrate (e.g., a sheet of metal suchas aluminum, magnesium, copper, zinc, chromium, nickel, iron and analloy mainly consisting of them as well as a printed board, plastic,glass, silicon wafer and carbon whose surface has been treated with anyof the above metals), by an appropriate means such as roller, rollcoater, spin coater, curtain-roll coater, spraying, electrostaticcoating, dip coating and silk printing, and then, optionally aftersetting, dried to give a resist material (film).

[0115] The aqueous resin composition may be prepared by dissolving ordispersing the positive sensitive resin composition in water. Theaqueous composition may be handled in a similar manner to a commonphotosensitive material for electrodeposition and may be used as anelectrodeposition paint. The positive sensitive resin composition may bedissolved or dispersed in water by neutralizing an anionic group such asa carboxyl group in the positive sensitive resin composition with analkali (neutralizing agent).

[0116] Examples of such an alkali neutralizing agent may bemonoethanolamine, diethanolamine, triethylamine, diethylamine,dimethylaminoethanol, cyclohexylamine and ammonia. The amount of theneutralizing agent is generally 0.2 to 1.0 equivalent, preferably 0.3 to0.8 equivalent to 1 equivalent of an ionic group in the positivesensitive resin composition.

[0117] The ionic-group-containing resin may preferably contain acarboxyl group in such a proportion that the acid value of the resin isabout 30 to 700 mgKOH/g, and particularly about 40 to 600 mgKOH/g. Ifthe acid value is less than about 30, an uncured film may be removed, bytreating with a developing solution, too insufficiently to adequatelyremove copper in a subsequent etching step. On the other hand, if theacid value is more than about 700, the resist film region (cured filmregion) may be removed too easily to form a satisfactory copper circuit.

[0118] An electrodeposition paint may be an anion electrodepositionpaint at pH 7 to 9, in which a bath concentration (solid concentration)is adjusted to 3 to 25 wt %, and particularly 5 to 15 wt %.

[0119] An electrodeposition paint may be, for example, applied to aconductor surface as a matter to be coated as follows. First, bath pHand concentration are adjusted to the above ranges and the bathtemperature is controlled to be 15° C. to 40° C., preferably 15° C. to30° C. Then, a substrate (conductor) to be painted is immersed as ananode in the electrodeposition bath controlled as described above, and adirect current of 5 to 200 volts is applied. An appropriateelectrification time is 10 seconds to 5 minutes. A film thickness to beformed is generally 0.5 to 50 μm, particularly 1 to 15 μm as a drythickness.

[0120] After electrodeposition, the coated matter is pulled up from theelectrodeposition bath and washed with water. Then, moisture and othersare removed by, e.g., hot air drying. The conductor may be a conductivematerial such as a metal, carbon and stannic oxide, or a plastic orglass on whose surface is fixed any of the above materials by, forexample, laminating or plating.

[0121] Besides the above applications, the composition of this inventionmay be applied to a transparent resin film to be a base film layer, suchas a polyester resin (e.g., polyethylene terephthalate), a (meth)acrylicresin, polyethylene and-polyvinyl chloride resin, using an appropriatemeans such as a roll coater, a blade coater and a curtain flow coater,and then dried to form a resist film having about 2 to 15 μm of drythickness, on whose surface is then applied a protective film to providea dry film resist.

[0122] After peeling the protective film off, the dry film resist may beapplied to a substrate as described above by an appropriate techniquesuch as thermocompression bonding in a manner that the resist film facesthe substrate, to form a resist film. With or without peeling the basefilm layer off, the resist film thus obtained may be exposed byirradiating with an active energy beam according to an image asdescribed for the electrodeposition film, and developing the resist film(over the base film when it has not been removed), to form an image.

[0123] The composition of this invention may be used in a variety ofapplications utilizing a well-known exposure-based lithographytechnique, such as a resist material for an electron device, a machineplate material (e.g., a flat plate or a plate material for reliefprinting and a PS plate for offset printing), an information recordingmaterial and a material for fabricating a relief.

[0124] Specifically, it may be used for printing and forming a patternsuch as an insulating pattern formed on a substrate surface including ablack matrix insulating pattern, an insulating pattern for a colorfilter, a pattern for covering an electron device (a film forsoldering), a ceramic or fluorescent-substance insulating pattern and abarrier pattern for a display panel, as well as a pattern on aninsulating substrate including a plastic circuit board and a plasticbuild-up board. For example, it may be used for forming a conductivepattern for a black matrix, a conductive pattern for a color filter, aconductive pattern for different display panels and a conductive patternformed on a plastic board or a plastic build-up board.

[0125] An typical example of pattern forming for a liquid resist or dryfilm resist using the composition of this invention will be described.

[0126] A pattern forming process using a liquid resist:

[0127] A pattern may be formed by a process consisting essentially ofthe steps of:

[0128] (1) applying the above liquid positive sensitive resincomposition to a substrate surface to form a resist film;

[0129] (2) irradiating the resist film on the substrate with an activeenergy beam such as ultraviolet laser, visible light (e.g.,monochromatic light within a visible region of 400 to 600 nm or mixedlight thereof, or Ar laser having an emission line in the visibleregion) and heat-ray laser, directly or via a mask film to form adesired pattern (image) on the film; and

[0130] (3) developing the resist film to form a resist pattern on thesubstrate.

[0131] These steps will be described in terms of, for example, asubstrate in a copper-coated laminate for a printed circuit having anon-penetrating hole and/or a through hole.

[0132] In step (1), a liquid positive sensitive resin composition may beapplied to a substrate by an appropriate application technique such as aroller, a roll coater, a spin coater, a curtain roll coater, spraying,electrostatic coating, dip coating, silk printing and electrodeposition,and then, after setting as necessary, it may be heated to give a resistfilm.

[0133] Heating may be conducted under a temperature condition which maysubstantially initiate a crosslinking reaction between the copolymer andthe ether-bond-containing unsaturated compound, e.g., at about 60° C. toabout 150° C. for about 1 to about 30 minutes.

[0134] In step (2), an active energy beam may be irradiated by anappropriate technique such as irradiation via a photomask or directdrawing by laser scanning.

[0135] An ultraviolet-ray source may be selected from conventionallyused ones such as an extra-high, high, medium or low pressure mercurylamp, a chemical lamp, a carbon arc lamp, a xenon lamp, a metal halidelamp, a fluorescent lamp, a tungsten lamp and solar light, and a varietyof lasers.

[0136] An ultraviolet-ray dose is generally 0.5 to 2,000 mJ/cm²,preferably 1 to 1,000 mJ/cm².

[0137] Heat rays may be, for example, semiconductor laser (830 nm), YAGlaser (1.06 μm) or infrared ray.

[0138] A heat-ray dose is generally 1 to 10,000 mJ/cm², preferably 10 to5,000 mJ/cm².

[0139] A visible light source may be a light obtained by cutting UVthrough a UV blocking filter from a light from a source such as anextra-high, high, mediumor low pressure mercury lamp, a chemical lamp, acarbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp,a tungsten lamp and solar light, and a variety of lasers having anemission line within a visible region of 400 to 700 nm. Among others, ahigh-power and stable laser beam such as argon laser (emission line: 488nm, 514.5 nm) and the second harmonic of YAG laser (532 nm) ispreferable.

[0140] A visible-light dose is generally 0.5 to 2,000 mJ/cm², preferably1 to 1,000 mJ/cm².

[0141] The resist film irradiated with an active energy beam is heatedpreferably under a temperature condition which can cause cleavage of thecrosslink structure in the cured film in the presence of an acidgenerated by the irradiation, e.g., at about 60° C. to about 150° C. forabout 1 minute to about 30 minutes.

[0142] Instep (3), an alkali or organic-solvent developing solution maybe used for developing.

[0143] Alkali developing solutions which may be used include an aqueoussolution of monomethylamine, dimethylamine, trimethylamine,monoethylamine, diethylamine, triethylamine, monoisopropylamine,diisopropylamine, triisopropylamine, monobutylamine, dibutylamine,monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol,diethylaminoethanol, ammonia, sodium hydroxide, potassium hydroxide,sodium metasilicate, potassium metasilicate, sodium carbonate,tetramethylammonium hydroxide or tetraethylammonium hydroxide.

[0144] A concentration of the alkali compound is preferably 0.05 to 10wt %.

[0145] Organic solvents which may be used include hydrocarbons such ashexane, heptane, octane, toluene, xylenes, dichloromethane, chloroform,carbon tetrachloride and trichloroethylene; alcohols such as methanol,ethanol, propanol and butanol; ethers such as diethyl ether, dipropylether, dibutyl ether, ethyl vinyl ether, dioxane, propylene oxide,tetrahydrofuran, cellosolve, methyl cellosolve, butyl cellosolve,methylcarbitol and diethylene glycol monoethyl ether; ketones such asacetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone andcyclohexanone; esters such as methyl acetate, ethyl acetate, propylacetate and butyl acetate; and others such as pyridine, formamide andN,N-dimethylformamide.

[0146] Developing may be conducted by spraying a developing solution onthe film or immersing it in the solution at a developing-solutiontemperature of about 10 to 80° C., preferably 15 to 50° C. for about 10seconds to 60 minutes, preferably 15 seconds to 20 minutes, depending onthe type of the resist film used.

[0147] The developed resist film is washed with water and dried by, forexample, hot air, to form a desired pattern (image) on the substrate. Itmay be, as necessary, etched to remove an exposed conductive part, andthen the resist film may be removed to provide a printed circuit board.For example, when the conductive film on the printed circuit board iscopper, the exposed conductive film may be removed with an acidicetchant such as cupric chloride or an ammonia etchant.

[0148] After the etching, the remaining resist film may be, asnecessary, removed. The remaining resist film may be removed with anaqueous alkali or acid solution or a variety of organic solvents.

[0149] A process for forming a pattern using a dry film resist:

[0150] A pattern may be formed by a process consisting essentially ofthe steps of:

[0151] (1) applying the above positive sensitive resin composition to asupporting substrate surface to form a positive dry film comprising asolid positive sensitive resin film;

[0152] (2) sticking the dry film on a substrate surface to be stuck in amanner that the substrate surface faces the resin film of the dry film;

[0153] (3) irradiating the dry film surface with an active energy beamdirectly or via a mask film with or without peeling off the supportingsubstrate of the dry film, to form a desired pattern; and

[0154] (4) developing the resist film, after peeling off the supportingsubstrate when it has not been removed in the step (3), to form a resistpattern on the substrate.

[0155] This process will be described in terms of, for example, asubstrate in a copper-coated laminate for a printed circuit having anon-penetrating hole and/or a through hole.

[0156] Sticking in step (2) may be conducted by superposing the film onthe substrate surface to be stuck in a manner that the substrate surface(e.g., a conductive substrate surface having a non-penetrating holeand/or a through hole) faces the positive sensitive resin film surfaceof the dry film, and then thermally laminating them while pressing themon the side of the supporting substrate surface of the dry film to stickthe substrate surface and the resin film layer surface together. Thermallamination may be conducted by, for example, heating the substratesurface and/or heating it from the side of the supporting substratesurface of the dry film. A heating temperature is generally 60 to 150°C., particularly 80 to 120° C.

[0157] In sticking the dry film on the substrate surface, the substratesurface may be treated with a liquid such as an adhesion promotingsolution described in U.S. Pat. No. 3,645,772 to Jones or a solvent fora resist layer described by Fickes, or a swelling agent, to improveadhesiveness of the substrate surface to the dry film. A vacuumlaminating apparatus may be used for adhesion. When using UV or visiblelight, the liquid may be photosensitive as disclosed in U.S. Pat. No.3,629,036 to Jsaacson.

[0158] Heating may be conducted under a temperature condition which maysubstantially initiate a crosslinking reaction between the copolymer andthe ether-bond-containing unsaturated compound, e.g., at about 60° C. toabout 150° C. for about 1 to about 30 minutes.

[0159] In step (3), the supporting substrate layer of the dry film ispeeled off from the positive sensitive resin film layer. This operationmay be conducted after irradiation with an active energy beam describedbelow.

[0160] Then, the substrate is irradiated with an active energy beamdirectly or via mask film to provide a desired pattern (image). Theactive energy beam may be selected from those described above. Its doseand irradiation procedure may be as described above.

[0161] The substrate irradiated with an active energy beam is heatedpreferably under a temperature condition which can cause cleavage of thecrosslink structure in the cured film in the presence of an acidgenerated by the irradiation, e.g., at about 60° C. to about 150° C. forabout 1 to 30 minutes.

[0162] The substrate is developed, after peeling off the supportingsubstrate when it has not been removed, to form a resist pattern on thesubstrate. Developing may be conducted using the processing solutiondescribed above under the conditions described above.

[0163] As described for pattern forming for a liquid resist, after theabove steps, the substrate may be, as necessary, etched to remove theexposed conductive part, and then, the resist film may be removed toprovide a printed circuit board.

[0164] After the above etching step, the remaining resist film may be,as necessary, removed.

[0165] Thus, the process for forming a resist pattern may provide aprinted circuit board on which a good fine-line circuit pattern isformed, using a copper-coated laminate substrate for a printed circuithaving a through hole and/or a non-penetrating hole as a substrate,without melting copper inside a through hole, if present, which maycause disconnection. Furthermore, since the through hole, thenon-penetrating hole and the fine-line circuit pattern of the printedcircuit board are adequately coated with a resist film, a solder resistinsulating film may be provided, which is extremely reliable in electricinsulation and chemical resistance.

[0166] This invention will be specifically described with reference toExamples. They are, however, only descriptive, and thus should not beinterpreted to be restrictive in any manner.

EXAMPLE 1

[0167] Into a 1,000 mL (inner volume) four-necked flask equipped with anagitator, a thermometer, a condenser and a 500 mL (inner volume)dropping funnel was charged 200 mL of tetrahydrofuran, which was thenrefluxed with stirring by heating at an external temperature of 80° C.with a water bath. Into a separate 1,000 mL Erlenmeyer flask werecharged 134.2 g of 4-(1-methylethenyl)phenol (hereinafter, referred toas “PIPE”) (1.00 mol) purified by crystallization from its2-ethylhexanol solution, 143.8 g of methyl acrylate (1.67 mol) purifiedby distillation, 48.3 g of acrylic acid (0.67 mol), 16.4 gazobisisobutyronitrile (0.10 mol) as a radical-polymerization initiatorand 200 mL of tetrahydrofuran as a solvent.

[0168] The latter mixture was stirred until it became a solution. Thewhole solution was transferred in the dropping funnel in two portions,and was added dropwise in the above four-necked flask in such a ratethat refluxing was maintained. During the polymerization reaction, theinternal temperature rose from 72° C. at the beginning to 80° C. after 8hours. Continuing stirring, the water bath was removed and the reactionmixture was allowed to be cooled to room temperature (25° C.) over 2hours. The polymerization solution was poured into 2 L of n-hexane in a5 L beaker, to precipitate a product polymer. The precipitated polymerwas separated by filtration and again dissolved in 400 mL oftetrahydrofuran. The solution was poured into 2 L of n-hexane toprecipitate a solid. This procedure of filtration, separation andprecipitation were further repeated twice. At the end of the lastfiltration-separation, the solid was dried under a reduced pressure of100 mmHg at 100° C. for 2 hours to give 320.4 g of white polymer.

[0169] The results of ¹H-NMR, ¹³C-NMR and elementary analysis for thewhite polymer indicated that the polymer is a desired copolymer. FIGS. 1and 2 show ¹H-NMR and ¹³C-NMR spectra, respectively, for the copolymerin d₆-dimethyl sulfoxide. These NMR results showed that the compositionratios a, b and c of the structural units represented by formulas (1),(2) and (3) were 0.34, 0.48 and 0.18, respectively, which weresubstantially equal to the charging ratios for the starting materials.GPC analysis using polystyrene as a standard indicated that theweight-average molecular weight (Mw) was 10,000 and the molecular-weightdispersion (Mw/Mn) was 1.94. FIG. 3 shows the GPC analysis.

[0170] It was attempted to dissolve the copolymer in diethylene glycoldimethyl ether or 2-heptanone, and in both solvents, at least 50 % ofthe copolymer were dissolved.

[0171] The copolymer was dissolved in diethylene glycol dimethyl ether.The solution was applied on a quartz substrate with a spin coater in anamount giving a dry film thickness of 1 μm. It was heated at 120° C. for10 minutes to form a film. Its transmittance at 350 nm determined with aspectrophotometer for ultraviolet and visible region was 98% or higher.FIG. 4 shows the spectrochemical analysis in ultraviolet and visibleregion.

[0172] Its glass transition temperature determined with a differentialscanning calorimeter was 125° C. It was found stable up to 200° C. orhigher based on thermal stability determined with a differential thermalbalance. FIG. 5 shows the thermogravimetric analysis.

[0173] In diethylene glycol dimethyl ether solvent were dissolved 100 gof the copolymer (solid), 60 g of a divinyl ether compound (acondensation product of 1 mol of bisphenol A with 2 mol of 2-chloroethylvinyl ether) and 10 g of a photo acid-generating agent A represented bythe following structural formula:

[0174] to provide a 50 wt % organic-solvent resist solution of Example1.

[0175] The organic-solvent resist solution was roller-coated on acopper-coated laminate in an amount giving a dry film thickness of 6 μmand was cured by heating at 120° C. for 8 minutes to form a resist film.The substrate was irradiated with a beam from a high-pressure mercurylamp with a power of 100 mJ/cm²via a positive pattern mask(line/space=50/100 μm), and then was heated at 120° C. for 10 minutes.

[0176] The substrate was immersed in an alkali developing solution a,i.e., a 2.38 wt % aqueous solution of tetrahydroammonium hydroxide, at25° C. for 60 seconds for developing and removing the resist film in theexposed part. A line/space was as good as 50/100 μm.

[0177] The substrate was irradiated with an UV laser with a power of 100mJ/cm² instead of a high-pressure mercury lamp via a positive patternmask, giving a line/space of 50/100 μm. Then, it was developed with analkali solution as described above.

[0178] Then, the exposed copper film on the substrate was etched with asolution of cupric chloride at about 40° C. and the resist film waspeeled off with a 3% aqueous solution of sodium hydroxide to provide aprinted circuit board. The printed circuit had a good line/space of50/100 μm.

EXAMPLES 2 to 4

[0179] Reaction, work up, mixing and resist-film formation wereconducted as described in Example 1, except that PIPE, methyl acrylateand acrylic acid were charged in the amounts shown in Table 1 althoughthe total molar amount was the same as that in Example 1 (3.34 mol).

[0180] For a resulting copolymer, composition ratios, a yield, aweight-average molecular weight and molecular weight dispersion weredetermined as described in Example 1. It was evaluated for solventsolubility, a transparency, thermal stability and resist-filmperformance (line/space) as described in Example 1. The results of theseanalyses and evaluation are shown in Table 1 together with the resultsfor Example 1. A printed circuit board was fabricated as described inExample 1.

COMPARATIVE EXAMPLE 1

[0181] Reaction, workup, analyses, mixing, resist-film formation andevaluation were conducted as described in Example 1, except that223.8 gof PIPE (1.67 mol) and 143.8 g of methyl acrylate (1.67 mol) werecharged and acrylic acid was not used. Charging mole fractions, theresults of analyses for a product copolymer and evaluation forresist-film performance are shown in Table 1 together with the resultsfor Examples 1 to 4. A printed circuit board was fabricated as describedin Example 1.

COMPARATIVE EXAMPLE 2

[0182] Reaction, workup, analyses, mixing, resist-film formation andevaluation were conducted as described in Example 1, except that 223.8 gof PIPE (1.67 mol) and 120.4 g of acrylic acid (1.67 mol) were chargedand methyl acrylate was not used. Charging mole fractions, the resultsof analyses for a product copolymer and evaluation for resist-filmperformance are shown in Table 1 together with the results for Examples1 to 4 and Comparative Example 1. A printed circuit board was fabricatedas described in Example 1.

COMPARATIVE EXAMPLE 3

[0183] Reaction, workup, analyses, mixing, resist-film formation andevaluation were conducted as described in Example 1, except that 143.8 gof methyl acrylate (1.67 mol) and 120.4 g of acrylic acid (1.67 mol)were charged and PIPE was not used. Charging mole fractions, the resultsof analyses for a product copolymer and evaluation for resist-filmperformance are shown in Table 1 together with the results for Examples1 to 4 and Comparative Examples 1 and 2. A printed circuit board wasfabricated as described in Example 1. TABLE 1 Polymerization (Upper:charging ratio; Lower: composition ratio) Polymerization results MethylSolvent Thermal PIPE acrylate Acrylic acid Yield solubility Line/spaceTransparency stability Example a b c (g) Mw Mw/Mn (wt %) (μm/μm) (%/μm)(° C.) 1 0.30 0.50 0.20 320.4 10,000 1.94 >50 50/100 >98 >200 0.34 0.480.18 2 0.20 0.65 0.15 321.1  9,500 1.78 >50 50/100 >98 >200 0.24 0.620.14 3 0.40 0.40 0.20 324.3  9,800 1.85 >50 50/100 >98 >200 0.43 0.380.19 4 0.30 0.40 0.30 319.0  9,900 1.91 >50 50/100 >98 >200 0.33 0.390.28 Comp. 0.50 0.50 — 355.7 10,100 1.95 >50 Could not form a >98 >200Example 1 pattern Comp. 0.50 — 0.50 337.2 10,500 1.98 5 Could not forma >98 >200 Example 2 pattern Comp. — 0.50 0.50 257.4 12,200 2.05 15Could not form a >98 Example 3 pattern

EXAMPLES 5 TO 8

[0184] Reaction, workup, analyses, mixing, resist-film formation andevaluation were conducted as described in Example 1, except that methylacrylate was replaced with one of acrylates in Table 2 in a molefraction shown in Table 2. The results of analyses for productcopolymers and evaluation for resist-film performance are shown in Table2 together with the results for Example 1. A printed circuit board wasfabricated as described in Example 1.

COMPARATIVE EXAMPLE 4

[0185] Reaction, workup, analyses, resist-film formation and evaluationwere conducted as described in Example 1, except that 223.8 g of PIPE(1.67 mol) was charged, methyl acrylate was replaced with 213.8 g oftert-butyl acrylate (1.67 mol) and acrylic acid was not used. Theresults of analyses for a product copolymer and evaluation forresist-film performance are shown in Table 2 together with the resultsfor Examples 1 and 5 to 8. A printed circuit board was fabricated asdescribed in Example 1. TABLE 2 Polymerization (Upper: charging ratio;Polymerization results Lower: composition ratio) Solvent Thermal PIPE(Meth)acrylates Acrylic acid Yield solubility Line/space Transparencystability Exam. a Name b (c) (gram) Mw Mw/Mn (wt %) (μm/μm) (%/μm) (°C.) 1 0.30 Methyl acrylate 0.50 0.20 320.4 10,000 1.94 >5050/100 >98 >200 0.34 0.48 0.18 5 0.30 Methyl 0.50 0.20 338.6  9,8001.88 >50 50/100 >98 >200 0.33 methacrylate 0.51 0.16 6 0.302-Hydroxyethyl 0.50 0.20 350.1  9,900 1.95 >50 50/100 >98 >200 0.34acrylate 0.47 0.19 7 0.30 Ethyl acrylate 0.50 0.20 332.0  9,300 1.75 >5050/100 >98 >200 0.32 Methyl 0.46 0.22 methacrylate 8 0.30 n-Butylacrylate 0.50 0.20 345.6  9,200 1.76 >50 50/100 >98 >200 0.35 Methyl0.47 0.18 methacrylate Comp. 0.50 t-Butyl acrylate 0.50 0 410.7 11,0001.98 >50 Could not form a >98 >200 Exam4 0.54 0.46 0 pattern

EXAMPLE 9

[0186] Into a 1,000 mL (inner volume) four-necked flask equipped with anagitator, a thermometer and a condenser were charged 134.2 g of PIPE(1.00 mol), 143.8 g of methyl acrylate (1.67mol), 58.3 g of methacrylicacid (0.67mol), 16.4 g of azobisisobutyronitrile (0.10 mol) and 400 mLof tetrahydrofuran. The mixture was then heated with stirring at anexternal temperature of 80° C. with a water bath, and then reacted for 8hours while keeping the temperature. The reaction mixture was worked upas described in Example 1 to give a desired copolymer, for whichanalyses, resist-film formation and evaluation were conducted asdescribed in Example 1. The results of analyses for the copolymer andevaluation for resist-film performance are shown in Table 3 togetherwith the results for Example 1. A printed circuit board was fabricatedas described in Example 1. TABLE 3 Polymerization (Upper: chargingratio; Lower: composition ratio) Polymerization results Methyl SolventThermal PIPE acrylate (Meth)acrylic acids Yield solubility Line/spaceTransparency stability Example a b Name c (g) Mw Mw/Mn (wt %) (μm/μm)(%/μm) (° C.) 1 0.30 0.50 Acrylic acid 0.20 320.4 10,000 1.94 >5050/100 >98 >200 0.34 0.48 0.18 9 0.30 0.50 Methacrylic 0.20 328.2  9,5001.79 >50 50/100 >98 >200 0.35 0.46 acid 0.19

EXAMPLES 10 TO 13

[0187] Reaction, workup, analyses and evaluation were conducted asdescribed in Example 1, except that tetrahydrofuran was replaced withone of the solvents in Table 4 in an amount shown in Table 4 and areaction temperature and a reaction duration were changed as shown inTable 4. Composition ratios, yields, weight-average molecular weightsand molecular-weight dispersions for product copolymers and evaluationresults for resist-film performance are shown in Table 4 together withthe results for Example 1. These copolymers exhibited good solventsolubility, transparency and thermal stability as was in Example 1.Formation of a resist film and fabrication of a printed circuit boardwere conducted as described in Example 1. TABLE 4 Polymerization (Upper:charging ratio; Lower: composition ratio) Polymeri- Polymeri- MethylAcrylic zation zation Polymerization results PIPE acrylate acid Solventtemp. duration Yield Line/space Exam. a b c Name Amount (g) (° C.)(hour) (g) Mw Mw/Mn (μm/μm)  1 0.30 0.50 0.20 Tetrahydro- 400  80  8320.4 10,000 1.94 50/100 0.34 0.48 0.18 furan 10 0.30 0.50 0.202-Ethylhexanol 200 100  7 322.1 19,500 1.81 50/100 0.31 0.19 0.20 110.30 0.50 0.20 n-Butyl alcohol 600 110 12 319.9  7,600 1.83 50/100 0.320.47 0.21 12 0.30 0.50 0.20 Methyl isobutyl 180  90 20 318.6 21,000 2.0050/100 0.34 0.49 0.17 ketone 13 0.30 0.50 0.20 Diethylene 250 100 22314.1 14,000 1.99 50/100 0.33 0.48 0.19 glycol dimethyl ether

EXAMPLES 14 TO 18

[0188] Reaction, workup, analyses, mixing, resist-film formation andevaluation were conducted as described in Example 1, except thatazobisisobutyronitrile was replaced with one of theradical-polymerization initiators in Table 5 in an amount shown in Table5 and a reaction temperature and a reaction duration were changed asshown in Table 5. Composition ratios, yields, weight-average molecularweights and molecular-weight dispersions for product copolymers andevaluation results for resist-film performance are shown in Table 5together with the results for Example 1. These copolymers exhibited goodsolvent solubility, transparency and thermal stability as was inExample 1. Formation of a resist film and fabrication of a printedcircuit board were conducted as described in Example 1. TABLE 5Polymerization (Upper: charging ratio; Lower: composition ratio)Polymeri- Polymeri- Methyl Acrylic Radical-polymerization zation zationPolymerization results PIPE acrylate acid initiator temp. duration YieldLine/space Exam. a b c Name Amount (g) (° C.) (hour) (g) Mw Mw/Mn(μm/μm) 1 0.30 0.50 0.20 Azobisisobutyro- 16.4  80  8 320.4 10,000 1.9450/100 0.34 0.48 0.18 nitrile 14 0.30 0.50 0.20 Dimethyl 35.7 120  5320.9  6,800 1.81 50/100 0.33 0.49 0.18 azobisisobutyrate 15 0.30 0.500.20 Azobiscyclohexane- 24.4 140 15 313.7  9,600 1.83 50/100 0.31 0.470.22 carbonitrile 16 0.30 0.50 0.20 Benzoyl peroxide 12.0 100 20 315.625,000 2.00 50/100 0.35 0.50 0.15 17 0.30 0.50 0.20 Di-t-butyl peroxide14.4 160 10 311.1 10,000 1.99 50/100 0.33 0.47 0.20 18 0.30 0.50 0.20Peroxydiisopropyl 20.6  60  7 318.3  9,100 1.76 50/100 0.36 0.47 0.17dicarbonate

EXAMPLES 19 TO 37

[0189] Each copolymer powder obtained in Examples 1 to 18 was dissolvedin diethylene glycol dimethyl ether to prepare a 50 wt % solution. Tothe solution were added 60 g of the divinyl ether compound (acondensation product of 1 mol of bisphenol A with 2 mol of 2-chloroethylvinyl ether), 10 g of the photo acid-generating agent A andtriethylamine (0.8 mol per one carboxyl group in the copolymer), per 100g of the solid in the solution, and then the mixture was dispersed inwater to prepare an aqueous resist solution of one of Examples 19 to 37,giving a solid proportion of 20 wt %. Examples 19 to 37 sequentiallycorrespond to Examples 1 to 18; for example, Example 19 to Example 1,Example 20 to Example 2, and so forth.

[0190] A pattern was formed and a substrate thus obtained was evaluatedfor its performance (line/space) as described in Example 1, using aresist film prepared by anionic-electrodepositing a film 5 μm of drythickness on a copper-coated laminate substrate as an anode using eachaqueous resist solution of Examples 19 to 37 as an electrodepositionbath, washing it with water and curing it by heating at 120° C. for 8minutes, instead of a resist film in Example 1 prepared byroller-coating an organic-solvent resist solution on a copper-coatedlaminate in an amount giving a dry film thickness of 6 μm and curing itby heating at 120° C. for 8 minutes. All the substrates exhibited aline/space as good as 50 μm/100

EXAMPLES 38 TO 56

[0191] An organic-solvent resist solution prepared in each of Examples 1to 18 was applied with a bar coater to a polyethylene terephthalate filmin an amount giving a dry thickness of 10 μm, and then the film washeated at 120° C. for 10 minutes to give a dry film.

[0192] The dry film was applied on a copper-coated laminate using adry-film laminator and the polyethylene terephthalate film was peeledoff to provide a resist-film coated substrate. Then, the substrate wassubject to irradiation, developing, etching and film-peeling asdescribed in Example 1 to give a printed circuit board. For the board, apattern was formed and performance (line/space) was evaluated asdescribed in Example 1. All the board exhibited a line/space as good as50 μm/100 μm.

EXAMPLE 57

[0193] The organic-solvent resist solution was roller-applied to acopper-coated laminate in an amount giving a dry film thickness of 6 μmas described in Example 1 and then was cured by heating at 120° C. for 8minutes to give a resist film. It was irradiated with heat ray(wavelength: 839 nm, semiconductor laser, 1 J/cm²) over the resist filmsurface, giving a line/space of 50 μm/100 μm.

[0194] The substrate was immersed in an alkali developing solution a, at25° C. for 60 seconds for developing and removing the resist film in theexposed part as described in Example 1. A resist pattern with aline/space of 50/100 mm was formed. Thus, its resist performance wasgood.

[0195] Then, the substrate was etched with a solution of cupric chlorideat about 40° C. and the resist film was peeled off with a 3% aqueoussolution of sodium hydroxide to provide a printed circuit board. Theprinted circuit had a line/space of 50/100 μm, that is, a good wiringpattern could be formed.

EXAMPLES 58 TO 114

[0196] A resist pattern was formed as described in each of Examples 2 to56, except that UV irradiation was replaced with heat-ray irradiationdescribed in Example 57. All substrates exhibited good resistperformance, i.e., a line/space=50 μm/100 μm.

COMPARATIVE EXAMPLES 5 TO 8

[0197] Resist-pattern formation was attempted as described in each ofComparative Examples 1 to 4, except that UV irradiation was replacedwith heat-ray irradiation described in Example 57. For any substrate, apattern could not be formed.

EXAMPLE 115

[0198] In diethylene glycol dimethyl ether solvent were dissolved 100 gof the copolymer (solid) obtained in Example 1, 60 g of a divinyl ethercompound (a condensation product of 1 mol of bisphenol A with 2 mol of2-chloroethyl vinyl ether), 10 g of the above photo acid-generatingagent A and 1.5 g of a photosensitizing dye B represented by thefollowing structural formula:

[0199] to provide a 50 wt % organic-solvent resist solution.

[0200] The organic-solvent resist solution was roller-applied to acopper-coated laminate in an amount giving a dry film thickness of 6 μmand then was cured by heating at 120° C. for 8 minutes to give a resistfilm. The substrate was irradiated with argon laser (wavelength: 488 nm)with a power of 5 mJ/cm², giving a line/space of 50 μm/100 μm. Then, itwas heated at 120° C. for 10 minutes.

[0201] The substrate was immersed in an alkali developing solution a, at25° C. for 60 seconds for developing and removing the resist film in theexposed part as described in Example 1. A resist pattern with aline/space of 50/100 mm was formed. Thus, its resist performance wasgood.

[0202] Then, the substrate was etched with a solution of cupric chlorideat about 40° C. and the resist film was peeled off with a 3% aqueoussolution of sodium hydroxide to provide a printed circuit board. Theprinted circuit had a line/space of 50/100 μm, that is, a good wiringpattern could be formed.

EXAMPLES 116 TO 172

[0203] A resist pattern was formed as described in each of Examples 2 to56, except that the same amount of the photosensitizing dye B describedin Example 115 was added in a composition and UV irradiation wasreplaced with argon-laser irradiation described in Example 115. Allsubstrates exhibited good resist performance, i.e., a line/space=50μm/100 μm.

COMPARATIVE EXAMPLES 9 TO 12

[0204] Resist-pattern formation was attempted as described in each ofComparative Examples 1 to 4, except that the same amount of thephotosensitizing dye B described in Example 115 was added in acomposition and UV irradiation was replaced with argon-laser irradiationdescribed in Example 115. For any substrate, a pattern could not beformed.

What is claimed is:
 1. A positive sensitive resin composition comprisinga base polymer, an ether-bond-containing olefinic unsaturated compoundand an acid-generating agent, where the base polymer is a copolymercomprising the structural units represented by formula (1):

where R¹ is hydrogen or methyl and R² is C₁-C₆ straight or branchedunsubstituted alkyl or C₁-C₆ straight or branched substituted alkyl, andformula (3):

where R³ is hydrogen or methyl, wherein a, b and c are 0.05 to 0.7, 0.15to 0.8 and 0.01 to 0.5, respectively and a+b+c=1.
 2. A positivesensitive resin composition as claimed in claim 1 where a compoundingratio of the copolymer comprising the structural units represented byformulas (1) to (3) and the ether-bond-containing olefinic unsaturatedcompound is 0.5 to 50/99.5 to 50 wt % as a ratio ofcopolymer/unsaturated compound based on their total wt % values, and theamount of the acid-generating agent is 0.1 to 40 wt parts to 100 wtparts of the total amount of the copolymer and the olefinic unsaturatedcompound.
 3. A positive sensitive resin composition as claimed in claim1 where R² in the structural unit represented by formula (2) is C₁-C₆straight or branched unsubstituted alkyl or C₁-C₆ straight or branchedhydroxylated alkyl.
 4. A positive sensitive resin composition as claimedin claim 3 where R² in the structural unit represented by formula (2) isselected from the group consisting of methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl and 2-hydroxyethyl.
 5. Apositive sensitive resin composition as claimed in claim 1 where amaterial giving the structural unit represented by formula (2) is a(meth)acrylate selected from the group consisting of methyl acrylate,ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,isobutyl acrylate, sec-butyl acrylate, 2-hydroxyethyl acrylate, methylmethacrylate, ethyl methacrylate, n-propyl methacrylate, isopropylmethacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butylmethacrylate and 2-hydroxyethyl methacrylate.
 6. A positive sensitiveresin composition as claimed in claim 1 where for the copolymer, a informula (1) is 0.20 to 0.45, b in formula (2) is 0.25 to 0.70, and c informula (3) is 0.15 to 0.40, and a+b+c=1.
 7. A positive sensitive resincomposition as claimed in claim 1 where the copolymer comprising thestructural units represented formulas (1), (2) and (3) is an alternatingcopolymer comprising the structural units represented by formula (4):

where R¹ is hydrogen or methyl and R²is C₁-C₆ straight or branchedunsubstituted alkyl or C₁-C₆ straight or branched substituted alkyl, andformula (5):

where R³ is hydrogen or methyl, in which the total content of thesestructural units is at least 60 mol %.
 8. A positive sensitive resincomposition as claimed in claim 1 comprising a photosensitizer.
 9. Apositive sensitive resin composition as claimed in claim 8 where acompounding ratio of the copolymer comprising the structural unitsrepresented by formulas (1) to (3) and the ether-bond-containingolefinic unsaturated compound is 0.5 to 50/99. 5 to 50 wt % as a ratioof copolymer/unsaturated compound based on their total wt % values; theamount of the acid-generating agent is 0.1 to 40 wt parts to 100 wtparts of the total amount of the copolymer and the olefinic unsaturatedcompound; and the amount of the photosensitizer is 0.1 to 20 wt parts to100 wt parts of the total amount of the copolymer, the olefinicunsaturated compound and the acid-generating agent.
 10. A positivesensitive resin composition as claimed in claim 8 where R² in thestructural unit represented by formula (2) is C₁-C₆ straight or branchedunsubstituted alkyl or C₁-C₆ straight or branched hydroxylated alkyl.11. A positive sensitive resin composition as claimed in claim 10 whereR² in the structural unit represented by formula (2) is selected fromthe group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl and 2-hydroxyethyl.
 12. A positive sensitive resincomposition as claimed in claim 8 where a material giving the structuralunit represented by formula (2) is a (meth)acrylate selected from thegroup consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate,isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butylacrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, sec-butyl methacrylate and2-hydroxyethyl methacrylate.
 13. A positive sensitive resin compositionas claimed in claim 8 where for the copolymer, a in formula (1) is 0.20to 0.45, b in formula (2) is 0.25 to 0.70, and c in formula (3) is 0.15to 0.40, and a+b+c=1.
 14. A positive sensitive resin composition asclaimed in claim 8 where the copolymer comprising the structural unitsrepresented formulas (1), (2) and (3) is an alternating copolymercomprising the structural units represented by formula (4):

where R¹ L hydrogen or methyl and R² is C₁-C₆ straight or branchedunsubstituted alkyl or C₁-C₆ straight or branched substituted alkyl, andformula (5):

where R³ is hydrogen or methyl, in which the total content of thesestructural units is at least 60 mol %.
 15. A positive ultravioletsensitive resist comprising a composition as claimed in any of claims 1to 7, whose part irradiated with ultraviolet rays is soluble ordispersible in an organic solvent or an aqueous developing solution, andwhose unirradiated part is substantially insoluble and undispersible inan organic solvent or an aqueous developing solution.
 16. A positivethermally sensitive resist comprising a composition as claimed in any ofclaims 1 to 7, whose part irradiated with heat rays is soluble ordispersible in an organic solvent or an aqueous developing solution, andwhose unirradiated part is substantially insoluble and undispersible inan organic solvent or an aqueous developing solution.
 17. A positivevisible-light sensitive resist comprising a composition as claimed inany of claims 8 to 14, whose part irradiated with visible light issoluble or dispersible in an organic solvent or an aqueous developingsolution, and whose unirradiated part is substantially insoluble andundispersible in an organic solvent or an aqueous developing solution.18. An organic-solvent type resin composition which is prepared bydissolving or dispersing the positive sensitive resin composition asclaimed in any of claims 1 to 14 in an organic solvent.
 19. An aqueousresin composition which is prepared by dissolving or dispersing thepositive sensitive resin composition as claimed in any of claims 1 to 14in water.
 20. An aqueous resin composition as claimed in claim 19,wherein the dissolving or dispersing is carried out by neutralizing ananionic group in the positive sensitive resin composition with analkali.
 21. A positive dry film comprises a substrate and a resist film,where the resist film is formed by applying a positive sensitive resincomposition as claimed in any of claims 1 to 14 to a surface of thesubstrate.
 22. A process for forming a resist pattern consistingessentially of the steps of: (1) applying a positive sensitive resincomposition as claimed in any of claims 1 to 14 to a substrate surfaceto form a resist film; (2) irradiating the resist film on the substratewith an active energy beam directly or via a mask film to form a desiredpattern (image) on the film; and (3) developing the resist film to forma resist pattern on the substrate.
 23. A process for forming a resistpattern consisting essentially of the steps of: (1) applying a positivesensitive resin composition as claimed in any of claims 1 to 14 to asupporting substrate surface to form a positive dry film comprising asolid positive sensitive resin film; (2) stacking the dry film on ansubstrate surface to be stuck in a manner that the substrate surfacefaces the resin film of the dry film; (3) irradiating the dry filmsurface with an active energy beam directly or via a mask film with orwithout peeling off the supporting substrate of the dry film, to form adesired pattern; and (4) developing the resist film, after peeling offthe supporting substrate when it has not been removed in the step (3),to form a resist pattern on the substrate.